ActiveMQ Interview Questions
In this post we will look at ActiveMQ Interview questions. Examples are provided with explanation.
Q: What is Activemq?
A: Apache ActiveMQ is an open source message broker written in Java together with a full Java Message Service (JMS) client. It provides "Enterprise Features" which in this case means fostering the communication from more than one client or server.
Q: What is use of Activemq instead of other options like database?
A: Activemq is used to reliably communicate between two distributed processes. It can store messages in a database to communicate between to processes, but as soon as the message is received you'd have to delete the message. That means a row insert and delete for each message. When you try to scale that up communicating thousands of messages per second, databases tend to fall over.
Message oriented middleware like ActiveMQ on the other hand are build to handle those use cases. They asume that messages in a healthy system will be deleted very quickly and can do optimizations to avoid the overhead. It can also push messages to consumers instead of a consumer having to poll for new message by doing a SQL query. This further reduces the latency involved in processing new messages being sent into the system.
A: Java Message Service (JMS) is an application program interface (API) from Sun Microsystems that supports the formal communication known as messaging between computers in a network. Sun's JMS provides a common interface to standard messaging protocols and also to special messaging services in support of Java programs. ActiveMQ is based on JMS.
Q: How to get started with JMS?
A: Getting Started with JMS Messaging- ActiveMQ Hello World Tutorial